J I I . --------.. I \ --. ( \ . , , . .... . J .' .. \ , I '. .a . , \\ I { \ , " . "'- I , I \ ,....,, " "- ',- ,"- "- , , ",. , , -- - '- - -- - .: - ......,....... .,.0 ....:..." ,. -' . .' , , I I I , ."I . \ , ,. . . , , " ..: \ . . þ -.. .. "J .. . , . I r . f , , , . -; ... t . , i 0 , " - J , - .. .. I, ..... f ,I . " ", . . - . "'- ---.... -- . \ ..... - \. "- "- "0 , ..... '\. , -. " - ..... .\ . .. ..- . --. . .... . .. . .. . - .. . . . . . . -1 Preserve, which has protected wetlands and ten miles of natural coast. University of Tel Aviv. Like Yau, Perelman was a formidable problem solver. Instead of spending years con- structing an intricate theoretical frame- work, or defining new areas of re- search, he focussed on obtaining par- ticular results. According to Mikhail Gromov, a renowned Russian geome- ter who has collaborated with Perel- man, he had been trying to overcome a technical difficulty relating to Alexan- drov spaces and had apparently been stumped. "He couldn't do it," Gromov . d " I h I " sa!. t was ope esse Perelman told us that he liked to work on several problems at once. At Berkeley, however, he found himself returning again and again to Hamil- ton's Ricci -flow equation and the prob- lem that Hamilton thought he could solve with it. Some of Perelman's friends noticed that he was becoming more and more ascetic. Visitors from St. Petersburg who stayed in his apart- ment were struck by how sparsely fur- nished it was. Others worried that he seemed to want to reduce life to a set of rigid axioms. When a member of a hiring committee at Stanford asked him for a C.V. to include with requests for letters of recommendation, Perel- man balked. "If they know my work, they don't need my C.V.," he said. "If they need my C.V., they don't know k " my wor . Ultimately, he received several job offers. But he declined them all, and in the summer of 1995 returned to St. Petersburg, to his old job at the Stek- lov Institute, where he was paid less than a hundred dollars a month. (He told a friend that he had saved enough money in the United States to live on for the rest of his life.) His father had moved to Israel two years earlier, and his younger sister was planning to join him there after she finished college. His mother, however, had decided to remain in St. Petersburg, and Perel- man moved in with her. "I realize that in Russia I work better," he told col- leagues at the Steklov. At twenty-nine, Perelman was firmly established as a mathematician z and yet largely unburdened by profes- sional responsibilities. He was free to pursue whatever problems he wanted (/) to, and he knew that his work, should --' he choose to publish it, would be THE NEW YORKER, AUGUST 28, 2006 51